Some of the Conflicting Concepts Around Interchangeability

At the Biosimilar Multistakeholder Summit, a closed meeting of 17 executives that was held November 30–December 2 in San Diego, organized by StrategiX, a number of important issues were raised regarding the daunting question of interchangeability. In this post, we’ll address how interchangeability was framed at the conference.

Although the Biologics Price Competition and Innovation Act (BPCIA) tried to apply the concept of interchangeability, used in the generic marketplace approval process, to the more complicated biologics arena, few expected a smooth translation. In fact, the US Food and Drug Administration (FDA) has tacitly acknowledged the difficulty, when they postponed the release of their all-important guidance on the topic until late 2017.

The concept of interchangeability, as it applies to biosimilars, is unique to the US; the regulatory concept does not exist in Europe, where switching of products is not expressly prohibited. We assume that the FDA will eventually approve interchangeability in 2 ways: (1) tighter prespecified equivalence margins than now seen with conventional biosimilar testing and (2) additional clinical studies. Although manufacturers may decide someday to spend the additional money to to prove the extreme similarity of their agent to the originator, it may not have the impact on marketplace uptake that one might expect. For example, if a biosimilar product without the interchangeability designation is already approved upon the launch of the new biosimilar, and it is already being switched at the point of prescription, by the clinicians themselves, based on payer coverage policies, then what does the new product bring to the table?

If safety is is important to gauging the interchangeability of the product, this ignores the levels of confidence gained with the 10-year global experience with biosimilars—a virtually spotless record that seems to contradict the notion that interchangeability is important.

Another very interesting and valid consideration involves a bit of reverse logic regarding the standard biosimilar approval process. The biosimilar manufacturer does everything required to prove that their product is equivalent in safety and efficacy compared with the originator product. No manufacturer seeks to demonstrate that their biosimilar is not interchangeable with the originator product. If it was deemed not interchangeable, the participants agreed, the molecule would not be able to pass the basic test for biosimilarity.

Actions taken by US payers (e.g., CVS Health, UnitedHealthcare, the Department of Veterans Affairs) to exclude coverage from originator products should compel the move towards switching by the physician’s pen, in the absence of FDA action on interchangeability. By the time an interchangeable product is approved by the FDA, we may likely have a couple of biosimilars being used in this way already.